Many thanks John E for your very erudite history lesson. The passive partial vacuum system you introduced in Gates housing has never in many years of using it given me a single problem. Nor many of my clients. The valve is also one of the most durable.

Took this vacuum system idea long enough to become mainstream. Now with blinking lights, vacuum monitoring and special inflation is really just a distraction and unnecessary in my opinion. Still it is no harm. More choice more confusion when choosing which to go for. I would chose one that is simple, no electronics to fail or battery going flat. Just use it and forget it.

I like having an electronic indicator of the vacuum. Set up the camera the night before, and a quick turn on to see the vacuum is still in place in the am. Also before each dive on the boat lets me know all is still well.

Interests:User name says it all- Dive &amp; Golf, plus a little fishin' when I can.

Posted 11 November 2013 - 04:56 AM

I think you will find that doing a vacuum check to ensure that the seals on submersible enclosures are functioning correctly goes back a very long way. I spent a large chunk of my life as a Submarine Engineer Officer in the Australian Navy. The last thing we did before going to sea and diving after an extended period in harbour for maintenance was to close all the hatches, pull a vacuum inside the submarine and monitor over a period of time to ensure that none of the seals on hatches, periscopes etc were leaking air into the boat. This has been a standard maintenance procedure in submarines for a long time. If a vacuum check is good to keep me dry when the submarine dives (water in the people tank is not a good thing ) it's good enough to ensure my camera stays dry when I take it diving.

Interesting. I spend a good part of my life in the US Navy nuclear submarine service and never encountered such a procedure except in a shipyard during overhaul and compartment testing. Now if you're snorkeling at PD and the head valve goes shut for an extended period, you do get a rapid, unintended vacuum. Was your vacuum test done by compartment or on the entire boat at one time?

JohnE: Thanks for the background. What do you define as "extreme pressure"? I assume it's beyond normal rec. depths.

Interests:User name says it all- Dive &amp; Golf, plus a little fishin' when I can.

Posted 11 November 2013 - 05:14 AM

I like having an electronic indicator of the vacuum. Set up the camera the night before, and a quick turn on to see the vacuum is still in place in the am. Also before each dive on the boat lets me know all is still well.

One caveat with the Leak Sentinel system (Vivid Housings). When you turn the unit on, it senses the pressure in the housing as atmospheric pressure (1 bar) and measures vacuum relative to that pressure. So if you pull a vacuum at night and then turn the sensor off afterward, when you turn it on in the morning, it will sense the internal pressure (approx. 0.8 bar) in the housing and measure vacuum relative to that pressure. So, although you may have a vacuum in the housing, the sensor will indicate that there is not a sufficient vacuum in the housing and will blink red.

Although I have not dove the unit yet, I plan to pull the vacuum at night after the unit is assembled for the next day and monitor it for 30-60 minutes. If all is well, I'll turn the unit off to conserve battery, but retain the vacuum in the housing. The next morning, I'll bleed air into the housing to eliminate the vacuum as evidenced by the hissing sound. If there is no hissing, then I have a problem. Then reestablish the vacuum with the proper green light indication. Using this procedure, I should get a 14 day dive trip out of one battery, or at least I hope to do so.

its really not that much difference with passive system. i could pull partial vacuum the night before or even two days before. just before the dive or during the morning prep i plug in my hand pump with an analog gauge or a digital gauge. i prefer all mechanical. if fact i sometimes check if the vacuum is still there just before i jump in by unlatching the snaps or try pull out the port. of course if you have vacuum you will have resistance and usually can't be pull apart. simple physics. i am okay with electronics and i have both but if i were in a one month trip in the middle of nowhere i think the passive or mechanical system offers me less trouble or risk. each to their own and as long as it works and let one concentrate on the shot rather than having constantly worry about the vacuum. bring spare batteries.

its really not that much difference with passive system. i could pull partial vacuum the night before or even two days before. just before the dive or during the morning prep i plug in my hand pump with an analog gauge or a digital gauge. i prefer all mechanical. if fact i sometimes check if the vacuum is still there just before i jump in by unlatching the snaps or try pull out the port. of course if you have vacuum you will have resistance and usually can't be pull apart. simple physics. i am okay with electronics and i have both but if i were in a one month trip in the middle of nowhere i think the passive or mechanical system offers me less trouble or risk. each to their own and as long as it works and let one concentrate on the shot rather than having constantly worry about the vacuum. bring spare batteries.

With the electronic system you do not have to carry your gauge or unsnap jyour housing or try to remove your port (sounds unwise and a bit brutal). It also tells if you start to loose the vacuum with a warning light. So I know IMMEDIATELY before I go in the water that my vacuum is still intact (and nothing has gone awry in the time period immediately before going in the water).

One caveat with the Leak Sentinel system (Vivid Housings). When you turn the unit on, it senses the pressure in the housing as atmospheric pressure (1 bar) and measures vacuum relative to that pressure. So if you pull a vacuum at night and then turn the sensor off afterward, when you turn it on in the morning, it will sense the internal pressure (approx. 0.8 bar) in the housing and measure vacuum relative to that pressure. So, although you may have a vacuum in the housing, the sensor will indicate that there is not a sufficient vacuum in the housing and will blink red.

Although I have not dove the unit yet, I plan to pull the vacuum at night after the unit is assembled for the next day and monitor it for 30-60 minutes. If all is well, I'll turn the unit off to conserve battery, but retain the vacuum in the housing. The next morning, I'll bleed air into the housing to eliminate the vacuum as evidenced by the hissing sound. If there is no hissing, then I have a problem. Then reestablish the vacuum with the proper green light indication. Using this procedure, I should get a 14 day dive trip out of one battery, or at least I hope to do so.

I cannot comment on how other systems work.

I have used the System this summer.

My general was to vacuum it in the evening before. Then I simply let it blink the night through and between dives ( if I did not have to open the Housing).

The Cell is still going strong. So, it does not really seem to be an issue.

back to the subject, i had leak in my nimar housing twice in the past (with nikon d 80). im not using it anymore,because upgraded to aquatica. first leak was due to main o-ring failure, which slipped out of its place right before the closing of the housing (or, during it!), and second time it was failure of the o-ring on on-off command. in first case, flooding was something like 1 cubic centimetre per second, and in second case one drop every few seconds, directly on the shutter (because it is placed in the middle of on-off command on the body). fortunatelly, in both cases managed to save the camera, because it was visually obvious that there is a leak.(transparent housing) housing is still healty, because it has no electroparts. even in the case of flooding drops directly on the shutter, after carefull rinsing of the shutter (body turned upside-down) and sensitive blowing with the air from the cylinder, D80 still functioning perfectly

Interesting. I spend a good part of my life in the US Navy nuclear submarine service and never encountered such a procedure except in a shipyard during overhaul and compartment testing. Now if you're snorkeling at PD and the head valve goes shut for an extended period, you do get a rapid, unintended vacuum. Was your vacuum test done by compartment or on the entire boat at one time?

JohnE: Thanks for the background. What do you define as "extreme pressure"? I assume it's beyond normal rec. depths.

Seal Check is an active, external vacuum monitoring system. It allows you, the user, to make a go/no go decision on housing integrity by monitoring the vacuum level in the housing.

An internal vacuum check takes this decision from you. You must trust the designer of the kit.

We opted for the external system because other factors can influence the result. Temperature changes, for example, change the level of vacuum in the housing (PV=nRT). The smaller the housing, the greater effect temperature changes will have on the system.

Also the larger Gates housings take forever to pull a reasonable vacuum with a hand pump. An electric pump is necessary.

I have to say the Seal Check is one of my favourite pieces of kit, as John said when shooting on a big production knowing that the housing is not going to leak takes a huge stress off. Mine has proved its worth too and identified a issues before jumping in on two occasions and they issues weren't obvious at all.

Diving on the Damai (1), fell down in the camera room holding two housings, my 7D housing and my wife's video housing. The video housing was held up in the air, my head and the 7D hit the floor. Apparently the 45 finder on the 7D had enough torque on it to unseat slightly the clear back on the housing. No leak in the rinse tank nor at 10 feet but at about 80 feet I could see water pouring in around the o-ring that holds the plexiglass back in place. Pretty sure that a vacuum check would have seen this but not sure since it took a lot of pressure to push the o-ring from the groove and allow the water to get in, not sure if I could have gotten enough DeltaP to see the leak.

Surely the "resistance" was because Hugyfot were forced into inventing the vacuum system when their original redesigned housing mechanism wasn't very good? The current popularity is because vacuum leak detectors have been taken up by some eminent practitioners recently...

... and (recession-led?) paranoia!

I never had a Hugyfot without Hugycheck. It's the reason I chose it!

I buy my own photographic kit. Diving equipment manufacturers and diving services suppliers get even-handed treatment from me whether they choose to advertise in the publications I write for or not. All the equipment I get on loan is returned as soon as it is finished with.Did you know you can now get Diver Mag as an iPad/Android app?

My wife's housing....she had a massage right before she put her housing together. Forgot the port oring...woops. Obviously the vacuum would have caught this.

Luckily the insurance replaced the whole housing instead of just the electronics, and I now use her old one for video....5d mark II. So in the end it worked out for me! So in this case, I am glad it happened...though I was pissed at the time.

Diving on the Damai (1), fell down in the camera room holding two housings, my 7D housing and my wife's video housing. The video housing was held up in the air, my head and the 7D hit the floor. Apparently the 45 finder on the 7D had enough torque on it to unseat slightly the clear back on the housing. No leak in the rinse tank nor at 10 feet but at about 80 feet I could see water pouring in around the o-ring that holds the plexiglass back in place. Pretty sure that a vacuum check would have seen this but not sure since it took a lot of pressure to push the o-ring from the groove and allow the water to get in, not sure if I could have gotten enough DeltaP to see the leak.

Bill

I was a witness to the sound of this event and can report that the video system was gallantly saved, and Bill's head did not spring any additional leaks.

Out of the 4 catastrophic floods at the Wetpixel Macro Workshop in Lembeh, one was a Nauticam system where the unfortunate user admits "I hurried and did not pay attention to a pinched o-ring."

The other was an Ikelite housing where the leak ended up being due to a defect in a dome at the attachment point.

“The world is a book and those who do not travel read only one page.” – St. Augustine

The video housing was held up in the air, my head and the 7D hit the floor.

That's called photographer's instinct.

Reminds me of last February. I was in Harbin, China to photograph the ice festival. Carrying my Hasselblad H4D in my hand. Walking along gingerly on shiny ice; in shoes that just had simple rubber soles. The guide called me to see something over on my right, my body changed direction, my shoes did not. Went down hard. My butt, back and head hit the ice simultaneously, with a solid crack. First instinct: is the camera OK? Everyone is worried about me. But, I'm lying on back, dazed, but testing the camera's functions. Yes, it was OK. Then I started to think about whether I was OK.

The guide told me later that I held the camera up the whole way down and gently cushioned its fall into my belly...

Had a headache and dizziness for a couple of days. But the camera was fine.

TImely topic....2 floods since 2000. First in 2000...rolled off the back of the boat with the rig. I have had it handed down ever since.

Most recent flood...3 weeks ago. Port came off the front of the camera when it was handed to me. Epic flood...when huge bubbles instantly come up you know it is not pretty. I had done a leak check in the rinse tank before getting on the boat and set it on the camera table on way out to divesite. Apparently port came loose somewhere on boat ride. Lesson learned....double check the port after boat rides. Thank goodness for equipment insurance.

And...have a vacuum system put it. Already have it ordered and housing in their hands. Not waiting on that one.

- First flood was in the rinse tank back in 2005 or 2006. Front port was knocked askew resulting in total flood.

- Second flood was about 6 months ago in Fiji. Still don't really know what happened, just saw bubbles coming from the top left of the housing where the surfaces mate. I was about 20 feet down and by the time I surfaced the entire housing was full. Opened it immediately, but didn't find anything obstructing the o-ring. I'm very careful with my gear, but I did just change from wide angle to macro, so obviously I did something wrong. BTW, the moisture alarm *did* go off, but the housing was already half full of water, so it really just added insult to injury. My flood insurance worked better than the moisture alarm thankfully

At any rate, the one thing I am certain of is a vacuum system would most likely have prevented both floods. My new Backscatter vacuum system arrives this Friday.